Don't output initial blurb in "quiet" mode
Don't output initial blurb in "quiet" mode

When logging to a file using the -l switch, we would still write an initial
banner to the file. This was never intended. Quiet should be really quiet
unless it experiences an error. Simplify the logging statement, to do nothing
if logevel is set to "WARNING" aka quiet.

Signed-off-by: Sebastian Spaeth <98dcb2717ddae152d5b359c6ea97e4fe34a29d4c@SSpaeth.de>

frioux/offlineimap,frioux/offlineimap